“A Hanford technician, wearing a protective mask fitted with the receiver of a two-way radio system, points to a blackboard drawing that demonstrates ‘how to talk your way around a huge nuclear reactor.’ When the reactor is loaded or unloaded, the fuel is handled by two men, one at the front and the other at the back of the reactor. The area around the rear face of the reactor is radio active, and a worker can remain there only for a limited time.”